The Unit of Geriatric Psychiatry performes research into several aspects of the aging process. In the area of Alzheimer's disease, studies have been performed examining the roles played by aluminum and fluoride. Examining the differential effects of neuroleptic drugs on the elderly, diagnostic criteria for tardive dyskinesia have been developed as well as research being performed to measure serum neuroleptic concentrations in older patients. Also, studies of cerebral ventricular size have been performed. Another major thrust of the work of this unit is in the area of brain tissue grafting in Parkinson's disease. Transplantation of fetal and adrenal medulla tissue continues into the brains of parkinsonism model rats and monkeys. Histology techniques continue to be refined and inroads into questions of immunocompatibility are being pursued. And finally, in work also designed to eventually correct neral damage, research into nerve repair is progressing.